Comparing Erg Chech 002 and Allende Meteorites
Posted by The Science Mall Team on 16th Feb 2025
Comparing Erg Chech 002 and Allende Meteorites
Meteorites act as time capsules from the early solar system. Two of the most informative are Erg Chech 002 (EC 002), an ungrouped achondrite crustal rock, and Allende, a CV3 carbonaceous chondrite rich in CAIs and chondrules.
Erg Chech 002 (EC 002)
What it is
Classification: Ungrouped achondrite (andesitic volcanic rock).
Mineralogy: Feldspar (plagioclase) and pyroxene in a silica-rich igneous matrix.
Parent body: Differentiated planetesimal with core–mantle–crust.
Discovery: Sahara Desert (Erg Chech region), 2020; ~31 kg recovered.
Age & significance
Age: ~4.566 Ga (U–Pb on zircon). EC 002 is the oldest known volcanic (igneous) rock from space, recording early crust formation and silica-rich volcanism on a now-destroyed protoplanet.
Field appearance
Typically weathered desert stones with muted tones; visible feldspar and pyroxene crystals; fusion crust commonly absent due to long exposure. Thin sections show coherent volcanic textures.
Allende (CV3)
Classification: Carbonaceous chondrite (CV3).
Components: Abundant chondrules and bright CAIs; organics present.
Fall: Witnessed fall, Chihuahua, Mexico, February 8, 1969; extensive fresh material recovered.
Age & significance
CAIs: ~4.567 Ga—the oldest dated solids in the solar system, condensed from the solar nebula. The bulk meteorite is primitive and undifferentiated, preserving nebular building blocks. Often called the “Rosetta Stone” of cosmochemistry.
Collector appearance
Distinct dark fusion crust; interior shows high-contrast speckling with white/blue-tinged CAIs and rounded chondrules—highly recognizable and popular with collectors.
Side-by-Side Comparison
| Aspect | Erg Chech 002 (EC 002) | Allende (CV3) |
|---|---|---|
| Type | Ungrouped achondrite (igneous crustal rock) | Carbonaceous chondrite (CV3, primitive) |
| Key Components | Plagioclase + pyroxene; andesitic composition | CAIs, chondrules, organics |
| Parent Body State | Differentiated (core–mantle–crust) | Undifferentiated (nebular aggregate) |
| Defining Age | ~4.566 Ga (oldest volcanic rock) | CAIs ~4.567 Ga (oldest solids) |
| Historical Note | Desert find, 2020 (~31 kg) | Witnessed fall, 1969; heavily studied |
| Look | Weathered; crystals visible; minimal fusion crust | Black fusion crust; bright CAIs; speckled interior |
| Why It Matters | Earliest planetary crust & differentiation | Earliest nebular condensates & organics |
What the meteorites Erg Chech 002 and Allende Each Teach Us
Planetary Differentiation (EC 002)
Demonstrates that silica-rich volcanism occurred on early planetesimals and preserves the chemistry of the first crusts.
Solar Nebula Record (Allende)
Captures the earliest condensates (CAIs) and molten droplets (chondrules), preserving pre-planetary materials.
Tips for Collectors & Educators
- Pair for teaching: Use EC 002 to illustrate crust formation and Allende for nebular origins—together they bracket “first solids” to “first crust.”
- Display notes: Label ages clearly (CAIs ~4.567 Ga; EC 002 igneous rock ~4.566 Ga) to avoid “oldest overall” vs “oldest volcanic” confusion.
- Context cards: Include parent-body state (differentiated vs primitive) and a brief classification line on every specimen card.